The brother of President George Bush, the Florida governor, Jeb Bush, has been instrumental in securing the release from prison of militant Cuban exiles convicted of terrorist offences, according to a new book. The Bush family has also accommodated the demands of Cuban exile hardliners in exchange for electoral and financial support, the book suggests.

Last year, after September 11, while the justice department announced a sweep of terrorist suspects, Cubans convicted of terrorist offences were being released from US jails with the consent of the Bush administration, according to the book, Cuba Confidential: Love and Vengeance in Miami and Havana, by Ann Louise Bardach, the award-winning investigative journalist who has covered Cuban and Miami politics for the New York Times and Vanity Fair.

The Bush family connections go back to 1984 when Jeb Bush began a close association with Camilo Padreda, a former intelligence officer with the Batista dictatorship overthrown by Fidel Castro.

Jeb Bush was then the chairman of the Dade county Republican party and Padreda its finance chairman. Padreda had earlier been indicted on a $500,000 (£320,000) embezzlement charge along with a fellow exile, Hernandez Cartaya, but the charges were dropped, reportedly after the CIA stated that Cartaya had worked for them.

Padreda later pleaded guilty to defrauding the housing and urban development department of millions of dollars during the 1980s.

The president's younger brother was also on the payroll in the 80s of the prominent Cuban exile Miguel Recarey, who had earlier assisted the CIA in attempts to assassinate President Castro.

Recarey, who ran International Medical Centres (IMC), employed Jeb Bush as a real estate consultant and paid him a $75,000 fee for finding the company a new location, although the move never took place, which raised questions at the time. Jeb Bush did, however, lobby the Reagan/Bush administration vigorously and successfully on behalf of Recarey and IMC. "I want to be very wealthy," Jeb Bush told the Miami News when questioned during that period.

In 1985, Jeb Bush acted as a conduit on behalf of supporters of the Nicaraguan contras with his father, then the vice-president, and helped arrange for IMC to provide free medical treatment for the contras.

Recarey was later charged with massive medicare fraud but fled the US before his trial and is now a fugitive.

Jeb Bush sealed his popularity with the Cuban exile community by acting as campaign manager for another prominent Cuban-American, Ileana Ros-Lehtinen, when she ran successfully for Congress.

George Bush Sr famously appeared with her during her campaign in Miami declaring: "I am certain in my heart I will be the first American president to step foot on the soil of a free and independent Cuba."

She has since lobbied successfully for the release of several exiles convicted of terrorist offences held in US jails but who now live freely in Miami.

Most controversially, at the request of Jeb, Mr Bush Sr intervened to release the convicted Cuban terrorist Orlando Bosch from prison and then granted him US residency.

According to the justice department in George Bush Sr's administration, Bosch had participated in more than 30 terrorist acts. He was convicted of firing a rocket into a Polish ship which was on passage to Cuba. He was also implicated in the 1976 blowing-up of a Cubana plane flying to Havana from Venezuela in which all 73 civilians on board were killed.

CIA memorandums strongly suggest, according to Bardach's book, that Bosch was one of the conspirators, and quotes the then secretary of state, Henry Kissinger, as writing that the "US government had been planning to suggest Bosch's deportation before Cubana airlines crash took place for his suspected involvement in other terrorist acts and violation of his parole".

Bosch's release, often referred to in the US media as a pardon, was the result of pressure brought by hardline Cubans in Miami, with Jeb Bush serving as their point man. Bosch now lives in Miami and remains unrepentant about his militant activities, according to Bardach.

In July this year, Jeb Bush nominated Raoul Cantero, the grandson of Batista, as a Florida supreme court judge despite his lack of experience. Mr Cantero had previously represented Bosch and acted as his spokesman, once describing Bosch on Miami radio as a "great Cuban patriot".

Other Cuban exiles involved in terrorist acts, Jose Dionisio Suarez and Virgilio Paz Romero, who carried out the 1976 assassination of the Chilean diplomat Orlando Letelier in Washington, have also been released by the current Bush administration.

The current administration also maintains a hard line on the continuing Cuban embargo despite the urgings of many in Mr Bush's own party to end it. The president's adviser, Karl Rove, "has urged him to fully accommodate hardliners in return for electoral victories for both his brother and himself", Bardach's book says.

For their help, many hardline Cuban-Americans have received plum jobs in the current administration: Mel Martinez, the Orlando Republican who arranged for the shipwrecked Cuban boy, Elian Gonzalez, to visit Disney World, was made housing secretary, while Otto Reich was awarded a one year recess appointment for the western hemisphere in the state department.